(a) Field of the Invention
The present invention relates to a roll forming apparatus, a method thereof, and a bumper beam manufactured by the method. More particularly, the present invention relates to a roll forming apparatus and a method thereof that make a composite panel by simultaneously roll forming upper and lower plates with thicknesses that are different from each other and a zigzag-shaped core panel, and welding them together, and to a bumper beam manufactured by using the composite panel.
(b) Description of the Related Art
Generally, a bumper unit of a vehicle minimizes physical damage of a vehicle body by being deformed elastically, and enhances safety of a driver or occupants by absorbing collision energy when an accident occurs. The bumper units are mounted at front and rear portions of the vehicle.
As shown in FIG. 1, such a bumper unit of a vehicle includes a bumper beam 201 mounted at front and rear portions of the vehicle and disposed along a width direction of the vehicle, an energy absorber 203 disposed in front of the bumper beam 201 and absorbing collision energy, a bumper cover 205 covering the bumper beam 201 and the energy absorber 203, and a stay 209 connecting the bumper beam 201 with a front side member 207.
Therefore, the energy absorber 203 is compressed and a part of the collision energy is absorbed by the energy absorber 203 when collision occurs. In addition, the other part of the collision energy that is not absorbed by the energy absorber 203 is absorbed by a vehicle body through the bumper beam 201 and the stay 209.
A straight-type beam, such as the bumper beam, is manufactured by a roll forming apparatus including more than 10 roll formers that consist of an upper roller and a lower roller and are disposed in series. The roll formers bend a panel into various shapes.
As shown in FIG. 2, such a roll forming apparatus includes an uncoiler 101 provided at a front portion in a process line and performing an uncoiling step S110 where a coil 100 is uncoiled to be a plate 102, and a straightener 103 provided at the rear of the uncoiler 101 in the process line and performing a straightening step S120 where the plate 102 supplied from the uncoiler 101 is straightened to be a panel 200.
In addition, the roll forming apparatus further includes a brake press 105 provided at the rear of the straightener 103 and performing a piercing step S130 where a plurality of holes for assembling a bumper beam are bored in the panel 200 supplied from the straightener 103.
In addition, the roll forming apparatus further includes a plurality of roll formers R1, R2, R3, R4, R5, R6, and R7 provided at the rear of the brake press 105 and performing a roll forming step S140 where the panel 200 supplied through the uncoiler 101, the straightener 103, and the brake press 105 is bent to form a bumper beam 300 shown in FIG. 3.
However, only one panel 200 can be manufactured by the conventional roll forming apparatus. Thus, two conventional roll forming apparatuses may be needed for manufacturing a bumper beam consisting of two panels. That is, two panels are separately manufactured by the two conventional roll forming apparatuses and are welded together. Therefore, productivity may deteriorate and product cost may rise.
Further, a new roll forming apparatus is needed in order to manufacture a bumper beam made of a sandwich-type composite panel.
The above information disclosed in this Background section is only for enhancement of understanding of the background of the invention and therefore it may contain information that does not form the prior art that is already known in this country to a person of ordinary skill in the art.